Listed in the accompanying table are weights (kg) of randomly selected U.S. Army male personnel measured in 1988 (from "ANSUR I 1988") and different weights (kg) of randomly selected U.S. Army male personnel measured in 2012 (from "ANSUR II 2012"). Assume that the two samples are independent simple random samples selected from normally distributed populations. Do not assume that the population standard deviations are equal. Complete parts (a) and (b). Click the icon to view the ANSUR data. a. Use a 0.05 significance level to test the claim that the mean weight of the 1988 population is less than the mean weight of the 2012 population. What are the null and alternative hypotheses? Assume that population 1 consists of the 1988 weights and population 2 consists of the 2012 weights. OA. Ho: ₁¹/₂ H₁: H₁ H₂ C OC. Ho: H₁ H₂ H₁: Hy

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ANSUR II 2012    ANSUR I 1988


91.0    100.3
100.8    70.9
88.1    72.7
86.4    103.7
90.6    66.5
103.3    74.9
98.2    64.9
97.0    78.8
69.7    62.1
78.7    85.2
71.5    74.5
88.9    89.0
85.6
86.6
109.9

 

 

**Hypothesis Testing for U.S. Army Personnel Weights**

In this activity, you'll explore data on the weights (in kilograms) of randomly selected U.S. Army male personnel. The data is collected from two different time points: 1988 ("ANSUR I 1988") and 2012 ("ANSUR II 2012"). These samples are assumed to be independent and drawn from normally distributed populations. It is also assumed that the population standard deviations are not equal.

**Objective:**
Use a 0.05 significance level to evaluate the hypothesis that the mean weight of the 1988 population is less than that of the 2012 population.

**Formulating Hypotheses:**

Determine the null and alternative hypotheses for the test, considering that:

- Population 1 represents the 1988 weights.
- Population 2 represents the 2012 weights.

**Hypothesis Options:**

A. 
- \( H_0 \): \( \mu_1 \neq \mu_2 \)
- \( H_1 \): \( \mu_1 > \mu_2 \)

B. 
- \( H_0 \): \( \mu_1 \leq \mu_2 \)
- \( H_1 \): \( \mu_1 > \mu_2 \)

C. 
- \( H_0 \): \( \mu_1 = \mu_2 \)
- \( H_1 \): \( \mu_1 < \mu_2 \)

D. 
- \( H_0 \): \( \mu_1 = \mu_2 \)
- \( H_1 \): \( \mu_1 \neq \mu_2 \)

**Choose the Correct Hypothesis:**

The task is to test if the mean weight for 1988 is less than that of 2012, so choose the appropriate hypotheses focusing on this comparison.
Transcribed Image Text:**Hypothesis Testing for U.S. Army Personnel Weights** In this activity, you'll explore data on the weights (in kilograms) of randomly selected U.S. Army male personnel. The data is collected from two different time points: 1988 ("ANSUR I 1988") and 2012 ("ANSUR II 2012"). These samples are assumed to be independent and drawn from normally distributed populations. It is also assumed that the population standard deviations are not equal. **Objective:** Use a 0.05 significance level to evaluate the hypothesis that the mean weight of the 1988 population is less than that of the 2012 population. **Formulating Hypotheses:** Determine the null and alternative hypotheses for the test, considering that: - Population 1 represents the 1988 weights. - Population 2 represents the 2012 weights. **Hypothesis Options:** A. - \( H_0 \): \( \mu_1 \neq \mu_2 \) - \( H_1 \): \( \mu_1 > \mu_2 \) B. - \( H_0 \): \( \mu_1 \leq \mu_2 \) - \( H_1 \): \( \mu_1 > \mu_2 \) C. - \( H_0 \): \( \mu_1 = \mu_2 \) - \( H_1 \): \( \mu_1 < \mu_2 \) D. - \( H_0 \): \( \mu_1 = \mu_2 \) - \( H_1 \): \( \mu_1 \neq \mu_2 \) **Choose the Correct Hypothesis:** The task is to test if the mean weight for 1988 is less than that of 2012, so choose the appropriate hypotheses focusing on this comparison.
The text provides instructions for statistical hypothesis testing regarding the mean weight of two different populations from 1988 and 2012.

1. **The test statistic is:** \[t = \_\_ \] (Round to two decimal places as needed.)

2. **The P-value is:** \[P = \_\_ \] (Round to three decimal places as needed.)

3. **State the conclusion for the test:**

   - **A.** Reject the null hypothesis. There is sufficient evidence to support the claim that the mean weight of the 1988 population is less than the mean weight of the 2012 population.
   
   - **B.** Reject the null hypothesis. There is not sufficient evidence to support the claim that the mean weight of the 1988 population is less than the mean weight of the 2012 population.

   - **C.** Fail to reject the null hypothesis. There is sufficient evidence to support the claim that the mean weight of the 1988 population is less than the mean weight of the 2012 population.
   
   - **D.** Fail to reject the null hypothesis. There is not sufficient evidence to support the claim that the mean weight of the 1988 population is less than the mean weight of the 2012 population.

4. **Construct a confidence interval appropriate for the hypothesis test in part (a):**

   - \[ \_\_ < \mu_1 - \mu_2 < \_\_ \]

   (Round to one decimal place as needed.)
Transcribed Image Text:The text provides instructions for statistical hypothesis testing regarding the mean weight of two different populations from 1988 and 2012. 1. **The test statistic is:** \[t = \_\_ \] (Round to two decimal places as needed.) 2. **The P-value is:** \[P = \_\_ \] (Round to three decimal places as needed.) 3. **State the conclusion for the test:** - **A.** Reject the null hypothesis. There is sufficient evidence to support the claim that the mean weight of the 1988 population is less than the mean weight of the 2012 population. - **B.** Reject the null hypothesis. There is not sufficient evidence to support the claim that the mean weight of the 1988 population is less than the mean weight of the 2012 population. - **C.** Fail to reject the null hypothesis. There is sufficient evidence to support the claim that the mean weight of the 1988 population is less than the mean weight of the 2012 population. - **D.** Fail to reject the null hypothesis. There is not sufficient evidence to support the claim that the mean weight of the 1988 population is less than the mean weight of the 2012 population. 4. **Construct a confidence interval appropriate for the hypothesis test in part (a):** - \[ \_\_ < \mu_1 - \mu_2 < \_\_ \] (Round to one decimal place as needed.)
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